Molded foam cushioning elements of the type set forth in U.S. Pat. No. 3,161,436, filed Dec. 15, 1964, have been used in automobile and vehicular applications to provide a vehicle seating assembly with both static and dynamic load supporting characteristics for passenger comfort. In such applications the element is supported by a rigid backing member forming part of the seat assembly frame for attachment to the vehicle body. In such cases the modulus of elasticity of the foam cushioning element and the thickness of the element is selected to provide a static deformation which conforms to and comfortably supports the weight/shape of different passengers. The cushioning elements have a modulus and are dimensioned to absorb dynamic impacts which are transferred through the vehicle suspension system into the seat assembly. In such cases the modulus and dimensions of the seating element are selected to absorb the impact loading without causing the foam element to fully compress and bottom out against the rigid backing member.
Such objectives can only be combined by use of foam elements with a thickness that will produce impact load absorption in a material of a modulus that has a comfortable feel under static load conditions. Such thickness of the foam element increases the weight of the vehicle seat assembly.
U.S. Pat. Nos. 2,251,318 and 4,545,614 disclose vehicle seat assemblies in which elastomeric webbing or strips are stretched between vehicle seat frame components to form a suspension for a seat cover. In the case of the '318 patent the strips are covered by a layer of foam material like spongy material which will impart static comfort to the assembly. The strap components are configured to yield to accommodate impact loads. The straps are reinforced by fabric to control against excessive deflection of natural rubber material of the straps.
The '614 patent uses strips or fibers of a material having a modulus at high deformation which is a multiple of natural rubber to control bottoming out of the suspension system. The use of strips, filaments or straps requires a cover to impart a smooth seating surface. Such covers can set to the shape of the underlying strip array following periods of use.